Affect means to

• A. to impact someone emotionally or mentally
• B. to produce a change in
• C. to disregard
• D. to measure

Answer: (B)

Affect is about causing a change. When something affects another thing, it brings about a difference or influence in it, whether that’s a change in mood, condition, or situation. That broad sense is why “to produce a change in” is the best fit here—it's not limited to emotions, but can describe any impact or alteration.

For example, a loud noise can affect your concentration, or weather can affect crops. The other options describe narrower ideas: “to impact someone emotionally or mentally” focuses specifically on emotion, “to disregard” means to ignore, and “to measure” means to assess. So the general meaning—to produce a change in—captures the core idea of affect.